The word "most infeasible" means something that is extremely difficult or impossible to achieve, but there are several antonyms or opposite words that convey different meanings. The antonyms for "most infeasible" could be achievable, feasible, practical, possible, or realistic, which suggest that the task or goal can be accomplished with some effort and planning. Other antonyms could be likely, or probable, which imply that the success of the task or goal has a higher chance of happening. Alternatively, some antonyms for "most infeasible" could be effortless, easy, simple, or uncomplicated, which denote that the task requires little effort or is straightforward.